Root Hair

1
Root Hair
2
Biology Additional 2008

• This is a power point showing most of the topics
  in a concise form
• Use it in conjunction with you revision guide

3
The definition of diffusion is. "the spreading
of a gas or any substance in solution from a
higher to a lower concentration." What has this
got to do with food, perfume, juice and more
importantly us! Well, let's start at the
beginning. All things on Earth are made of
particles. These are atoms and molecules. The
particles that make up a substance have varying
abilities to naturally move.
Diffusion in liquids Diffusion can also happen
in liquids. This is because the particles in
liquids can move around each other until they mix
evenly. Diffusion in liquids is slower than
diffusion in gases because the particles in a
liquid move more slowly. Diffusion does not
happen at all in solids because the particles in
a solid can only vibrate on the spot, rather than
being able to move from place to place.
4
We call this difference in concentrations, a
concentration gradient. 
Outside
Concentration Gradient
The steeper the gradient, the greater the
difference in concentration. We can represent
this using a diagram.
Out
Inside
In
Outside
Concentration Gradient
Out
Inside
In
5
Examples of diffusion in humans
Initially the concentration gradient would be
high with food particles diffusing in to the
blood.
How do we absorb food into the blood?
Small Intestine
B L O O D
 
 
Food particles
But, if the blood just received these particles
and remained stationary, a state of equilibrium
would then occur.
 
Therefore to overcome this, the blood is
constantly moving through the capillaries,
bringing new blood to the villi and taking blood
Concentration Gradient
Small Intestine
Small Intestine
Blood
6
(No Transcript)
7
 Where does the energy for active transport come
from?
The energy for active transport comes from
respiration
The faster the cell performs respiration, the
faster it generates energy
Aerobic Respiration requires a supply of glucose
and oxygen
The quicker they move, the quicker the cell can
perform respiration
These two substances are carried in the blood to
cells.
They have to move from the blood to the cells of
the body.
As you can see, the production and use of this
energy is linked in a cycle. This is one way the
body helps itself perform important functions.
8
Photosynthesis
Word equation
Light
Water Carbon dioxide
Glucose Oxygen Energy
Chlorophyll
Symbol equation
Light
C6H12O6
6O2
Energy
6H2O
6CO2
Chlorophyll
Factors limiting photosynthesis Three factors
limit photosynthesis from going any faster Light
level, carbon dioxide level, and temperature. 1)
Without enough light a plant cannot
photosynthesise very fast, even if there is
plenty of water and carbon dioxide. Increasing
the light intensity will make photosynthesis
faster.2) Sometimes photosynthesis is limited
by the level of carbon dioxide. Even if there is
plenty of light a plant cannot photosynthesise if
it has run out of carbon dioxide.3)Temperature
can be a limiting factor too. If it gets too cold
the rate of photosynthesis will slow right down
equally, plants cease to be able to
photosynthesise if it gets too hot. If you plot
the rate of photosynthesis against the levels of
these three limiting factors you get graphs like
the ones below.
9
Factors limiting photosynthesis Three factors
limit photosynthesis from going any faster Light
level, carbon dioxide level, and temperature. 1)
Without enough light a plant cannot
photosynthesise very fast, even if there is
plenty of water and carbon dioxide. Increasing
the light intensity will make photosynthesis
faster.2) Sometimes photosynthesis is limited
by the level of carbon dioxide. Even if there is
plenty of light a plant cannot photosynthesise if
it has run out of carbon dioxide.3)Temperature
can be a limiting factor too. If it gets too cold
the rate of photosynthesis will slow right down
equally, plants cease to be able to
photosynthesise if it gets too hot. If you plot
the rate of photosynthesis against the levels of
these three limiting factors you get graphs like
the ones below.
10
(No Transcript)
11
Remember!
12
Predator / Prey Relationship

• More prey than predators Due to energy loss at
  each trophic level
• Peak in the predator numbers after prey There has
  to be a critical number to support predator
  numbers
• Possible drop in numbers Disease, Climate,
  starvation

13
Pyramids of numbers will often be pyramid-shaped
like this - but not always.
SEE !
1Kg
10Kg
100Kg
1000Kg
Pyramids of biomass are always pyramid-shaped
                                             If
the producer is a large plant such as an oak
tree, the second layer of the pyramid
representing primary consumers (caterpillars in
this example) will be much larger than the base.
In this case it would make more sense to draw a
pyramid of biomass, which shows not the numbers
of organisms at each level, but the amount of
biological material.
14
Why does each tropic level in the Pyramid of
biomass get progressively smaller?
Answer the energy and material contained in the
biomass of the organism reduces at each level
Heat Radiation Respiration Undigested food
Pyramid of Biomass
Hawk
Heat Radiation Respiration Undigested food
Blue Tit
Caterpillar
Reflection Respiration
Oak
Suns Energy
15
How energy is lost
16
Examples of how energy is lost by various animals
100 Energy Entering the animal
Remember how to interpret and calculate losses
of Sankey diagrams
17
Compare a vegetarian to someone who eats meat
using a pyramids of biomass
Because there are more trophic levels more
energy is lost
Human
Vegetarian
Cow
Grass
Potato
18
What are the products of decomposition?
Carbon Dioxide
From respiration of the decomposers
Water
From respiration of the decomposers
Minerals
From the remains of the dead organism
Decay
Conditions required for decay
Remember what ever you need to stay alive so to
do the decomposers!
Oxygen
Decay
Warmth
Water
19
The Carbon Cycle
20
Key Words
CO2
CO2
Photosynthesis
Respiration
Builds up Glucose
Breaks down Glucose for energy
Fuels
Oil
CO2
Coal
Gas
Combustion
21

• Efficiency of food production
• The efficiency of food production can be improved
  by reducing the amount of energy lost to the
  surroundings. This can be done by  
• preventing animals moving around too much and
• keeping their surroundings warm.
• Mammals and birds maintain a constant body
  temperature using energy released by respiration.
  Their energy losses are high as a result. So
  keeping pigs and chickens in warm sheds with
  little space to move around allows more efficient
  food production. But this raises moral concerns
  about the lives of such animals. In reality, a
  balance must be reached between the needs of
  farmers and consumers, and the welfare of the
  animals involved.  
• Calculating energy efficiency  
• This cow has eaten 1000 kJ of stored energy in
  the form of grass, and excreted 630 kJ in the
  form of faeces, urine and gas. The energy stored
  in its body tissues is 40 kJ. So how much has
  been used up in respiration?  

Only 4 kJ of the original energy available to the
bullock is available to the next stage, which
might be humans. The efficiency of this energy
transfer is                                    
  
40
40 kJ
1000 kj
1000 kJ
630 kJ
22
Enzyme structure
Know the following- Active site Enzyme-substrate
complex Catalysts Biological catalysts
23
Factors affecting enzyme activity
1 Temperature 2 ph 3 Surface area
Urease
Amylase
Pepsin
1) Temperature
2) pH
24
3) increase surface area of the substrate i.e.
chew the food, this speeds up the enzymes action
25
Aerobic Respiration- this is an enzyme
controlled reaction
Why is this reaction important ?
Answer This reaction provides energy for living
cells Equation Glucose Oxygen Water
Carbon Energy Dioxide
Where does it take place?
Answer The Mitochondria which are organelles
found in the cytoplasm of living cells
Quick test! Match them
26
Enzyme in digestion
Know this!
Fill in
pH8
pH2
pH8
Make sure you are able to understand and be able
to describe how the model gut works
Know the pH of the gut
Why 30oC ?
Enzymes working towards their optimum
27
Industrial use of enzymes
Click to identify the enzymes
Remember the ending of an enzymes name is ASE

• Advantages
• Work at low temperature and pressures
• Cheap to use
• Only is a small amount is ever required

• Disadvantages
• Enzymes have to be monitored as they are
  sensitive to temp and pressure therefore this is
  expensive
• Expensive when in their pure form

28
Homeostasis
This is the way in which the body controls its
internal environment i.e. keeps it in a steady
state.
Waste products which have to be removed Carbon
dioxide This is a product of respiration and
is remove via the lungs when we breathe
out Urea This is produced by the liver as a
result of a process called DEAMINATION which
breaks down excess AMINO ACIDS. Urea is then
sent to the kidney via the blood stream where it
is excreted.
Internal conditions which have to be controlled
Water content Lost by Breathing , Sweating,
excess by the kidney, Gained by eating and
drinking. Salt / ion content Lost by kidney
and sweating Gained by eating and
drinking. Temperature Increased by
Shivering and shutting down the capillaries in
the skin Decreased by sweating and
opening up the skins capillaries
Control of internal glucose level to increase use
the hormone GLUCAGON to decrease
use the hormone INSULIN
29
Temperature Regulation
30
Regulating Blood Sugar level

• Make sure you Know how DIABETES is treated
• Regulate carbohydrate intake ( sugar consumption)
• 2) Inject insulin to reduce blood sugar level

31
Remember the human body needs to grow and repair
itself that means that all the new cells must
carry all the same information . Therefore all
new cells must carry 46 chromosomes. To produce
new cells, PARENT CELLS under go cell division
called MITOSIS
Know the order according to size
Single threads chromosomes
Single threads replicate
All 46 Sister chromatids line up down the middle
Single threads are pulled to opposite ends of the
cell
New nuclear membranes are formed, the cell
divides and two new DAUGHTER cells are formed
32
Stem Cells
Differentiation
These are stem cells, they have the ability to
change into any other specialised cell / tissue
Daughter cells resulting from mitosis ( Which
form the embryo of an new human being)
Differentiation Change to specialised cells
33
Instead of stem cells which have come from an
embryo. Body cells are cloned and can then be
used to treat a range of diseases
The future of stem cells Relying on the cloning
of the patients normal body cells
Therapeutic Cloning Know the name and how it may
be used Answer Why will the cells not be
rejected?
This section is differentiation which is the same
as the previous slide but the stem cells have
come from cloned human stem cells
34
Consider the problem the body has, during
reproduction if normal body cells fused together
then this would happen
Meiosis Reduction division
Takes place in ovaries and testis
23
23
Sperm
Egg
Fertilisation
46 chromosomes are the normal number for a human
being
46
Offspring
35
What did Gregor Mendel tell us!

• Characteristics in plants are determined by
  Hereditary Units
• Hereditary units are passed on from both parents
  one unit from each parent.
• Hereditary units can be Dominant or Recessive
• If an individual has both the Dominant and
  recessive unit then it is the dominant one which
  is expressed

We now know that the hereditary units are GENES
Gregor Mendels work was not recognised until
after his death as nobody new about DNA or GENE
36
Tall plants
Dwarf plants
Alternatively
TT
tt
Punnett method
Make sure you can work through this slide
37
Protein Synthesis
Gene
Gene replication by mRNA
mRNA leave the nucleus
tRNA attached amino acids
New protein being formed
mRNA
New protein strands
38
Inheriting Sex
Males carry XY chromosomes therefore ½ the
sperm carry an X chromosome and the other ½
carry the Y chromosome Females carry XX
chromosome all eggs carry a single X chromosome
Male
X
Y
Therefore you have a ½ chance of being a Male or
Female
X
XX
XY
Female
Male
Female
X
XY
XX
Female
Male
Chances during Fertilisation
39
Genetic Diseases
A genetic disease is one which is passed from
parents to children and is caused by faulty genes
( you cant catch them like the flu)
Cystic Fibrosis
This is a RECESSIVE disease. You can only get it
when you inherit two faulty recessive genes, one
from each parents who are themselves CARRIERS
Symptoms
How is it Inherited?

• Thick mucus lines the lungs and digestive
  system.
• Difficult to absorb oxygen and food, reduced
  growth rate
• High risk of lung infections and damage
• Life expectancy early 30s

Mother
F
f
Therefore you have a 1/4 chance of getting C.F.
FF Normal
Ff carrier
F
Father
ff C.F
Ff carrier
f
Chances during Fertilisation
40
Genetic Diseases
Huntingtons Disease
This is a Dominant disease. You can get it when
you inherit one faulty Dominant gene, one from
either parent who are themselves have the disease
Symptoms

• Fatal disease of the nervous system
• Appears between 30 and 50 years
• At this age the faulty gene may have been
  passed on to children

How is it Inherited?
Mother has the disease
H
h
Therefore you have a 1/2 chance of getting
Huntingtons
Hh Disease
hh Normal
h
Father is normal
hh Normal
Hh Disease
h
Chances during Fertilisation
41
DNA Fingerprint
A DNA fingerprint is constructed by first
extracting a DNA sample from body tissue or fluid
such as hair, blood, or saliva. The sample is
then segmented using enzymes, and the segments
are arranged by size using a process called
electrophoresis. The segments are marked with
probes and exposed on X-ray film, where they form
a characteristic pattern of black barsthe DNA
fingerprint. If the DNA fingerprints produced
from two different samples match, the two samples
probably came from the same person.
Is the Defendant Guilty or Innocent?